US2465921A - Method of cleaning flues - Google Patents

Description

1 March 29, 1949. T. J. PETERS METHOD OF CLEANING FLUES 2 Sheets-Sheet 1 Filed June 25, 1946 FlEL-i- INVENTORZ i 75a ATTORNEY.

March 29, 1949. T, J. PETERS METHOD OF CLEANING FLUES 2 Sheets-Sheet 2 Filed June 25, 1946 V INVENTORi 70M I P [TEE 5,

HIS ATTORNEY.

Patented Mar. 29, 1949 METHOD OF CLEANING FLUES Tom J. Peters, Chicago, 111., wignor to Carnegie- Illinois Steel Corporation, a corporation of New Jersey Application June 25, 1946, Serial No. 879,108

2 Claims. (01.1344) 1 This invention relates to a method of cleaning flues. such method being particularly advantageous when employed in the cleanin of rectangular dues of relatively small cross section,

such as those in open hearth checkers and blast furnace stoves.

Among the objects of the invention is the provision of an improved method of cleaning flues of the type described above, such method being characterized bythe ease with which it is carried out and the thoroughness 'of cleaning effected thereby. I

These and further objects of the invention will be more readily apparent in the following description of preferred embodiments of the method and apparatus which are illustrated in connection with the cleaning of lines in open hearth furnace checker work. It is to be understood, however, that the invention is not restricted to the particular illustrative example, but that it may be used to advantage in the cleaning of various types of fines, particularly flues of-relatively small cross section of which the inner surface includes one or more relatively sharp longitudinally extendin corners.

Air for combustion in an open hearth furnace is preheated by passage through hot checker bricks. The products of combustion are drawn off the furnace through checker bricks on the opposite side from the burner being operated, such hot products of combustion yielding, their heat to the checker bricks through which they pass on their way to the stack. The direction of the flow of the gas is periodically reversed, one set of checkers being cooled while the other is heated. It is inevitable that the products of combustion carry with them fumes and finely divided particles of oxides and slags. and that such fumes and particles gradually accumulate on the checker brick so that the checker openings eventually become coated therewith to such depth that the passage of gas is impeded. When such point of the operation of the furnace is reached, the furnace must be shut down and the checker work cleaned so as to remove such deposits from the flues of the checker work and to restore the flues to their original cross section.

Heretofore the flues and checker work has been cleaned by laborers using long, handled scrapers and brushes which were inserted in and pushed or pulled through each flue. Such work is difficult and time consuming, requiring, on a 110 ton capacity open hearth furnace, approximately 84 man hours with a lay-down period of the furnace of approximately 24. hours. Such method of cleaning is thus expensive, particularly because of the necessary relatively long period of inactivity of the furnace. In addition, it is not very effective, since the slag accumulations in the flues are hard and resist hand scraping and brushing.

, The present invention provides a power driven flue cleanin apparatus in which one or more flexible cleaning members, traveling. in an arc when free of contact with the flue, such are intersecting the surface of the flue, are caused initially to strike the flue surface with a substantial impact and subsequently to travel thereover with a wiping action. Such cleaning action preferably takes places in the vicinity of the one or more sharp longitudinally extending corners in the flue.- Such cleaning member thus cracks the accumulation of slag on the flue, by reason of its initial impact thereon, arid then removes it from the flue surface by its subsequent wiping action. The application of such member in the vicinity of the sharp corners, where the slag deposit is heaviest, is particularly advantageous since it was at such corner that previous flue cleaning methods were least effective.

The invention will be more readily understood by reference to the accompanying drawings, in which:

Figure 1 is a view in side elevation of a preferred embodiment of a cleaning head, portions of such head being shown in cross section, the section being taken along the line I-I of Figure 2;

Figure 2 is a view in end elevation of the portion of the cleaning head shown in Figure 1 in the vicinity of the cleaning means;

Figure 3 is a view in end elevation of a modified cleaning means;

Figure 4 is a view partially in side elevation and partially in section of the cleaning means shown in Figure 3, the section being taken along the line IV -IV of Figure 3;

Figure 5 is a view in isometric projection of a checker work with the preferred embodiment of the cleaning head inserted therein in operative position; and

Figure 6 is a schematic view showing the manner of operation of the preferred cleaning means, such view being an end elevation taken from a plane containing the end wall 54, and in the direction toward the reader, in Figure 5.

A preferred embodiment of the cleaning apparatus is shown in Figures 1 and 2. Such apparatus consists of a cleaning head having a casing consisting of a main portion 2 housing a rotary air motor supplied with compressed air through the flexible hose 6, the air supply being controlled by the shut-off valve 4. When used in the preferred manner the cleaning head as a whole is lowered progressively through each fluekeyed to shaft l and gear i8 being keyed to' shaft l4. The two outer ends of transverse shaft l4 are provided with reduced outer ends 20 which are threaded as shown to receive the disks 22 and the retaining nuts 24. The portions of shaft l4 between the further transverse housing portion l2 and the disks are protected by sleeves 26. In the embodiment shown in Figures 1 and 2 disks 22 are provided at the rim thereof with a plurality of short chains 28 spaced at equal angles around the disk. The chains are chosen of such length, as will be apparent from a consideration of Figures and 6, discussed below, that when the disks are rotating at suflicient speed to maintain the chains in a position substantially radial of the disks, the outer ends of the chains, when free of contact with the flue, travel in an are which intersects the sides of the flue into which the cleaning head is introduced.

In a further modification of the apparatus, shown in Figures 3 and 4, relatively stiff but flexible brushelements are employed on the disks rather than chains. In this modification the brush element carrying disks are designated 30, such disks being provided on their outer sides with counterbores 32 to receive the retaining nut 24 and thus to allow the disk closely to approach the flue end wall. Each disk 30 is provided with a plurality of radially disposed brush elements 34 on the rim, elements 34 conveniently being stiff wire brushes. Each disk may further be pro vided on its outer side with a plurality of equally spaced brush elements 36 extending parallel to the axis of the disk. Elements 36 may, as shown in Fig. 3, be spaced at varying radial distances on the disk in order completely to cover the flue end wall.

A typical manner of use of the cleaning apparatus of the invention is shown in Figure 5, in which there is shown the upper surface of a typical open hearth checker work 38 made up of checker bricks 40 laid in a basket weave. In such checker construction the flues 42 extend vertically and are square in cross section. The cleaning head is inserted into a flue as shown and is progressively let down into the flue by paying out the hose 6. The apparatus is designed so that the length of shaft I 4 is slightly smaller than the length of the flue dimension to which it is parallel. It will thus be seen that when the motor 2 is initiated and the disks 22 set in rapid rotation, the chains 28 will be impelled outwardly by centrifugal force, in the portions of their travel wherein they are free from contact with the flue walls, and that they will trike such walls in the vicinity of the opposed corners 43. of the flue. In Figure 5 the opposed walls 48 and 50 are designated side walls and the opposed walls 52 and 54 are designated end walls.

The manner in which the flexible cleaning members function to remove the deposits 46 of slag and the like from the flue. particularly at the corners will be somewhat clearer by consideration of Figure 6, in which the modification employing chains as the cleaning members is illustrated. It will be seen that but for the dis turbance in their position caused by contact with the flue walls, the chains 28, which in Figure 6 are shown traveling counterclockwise, tend" to occupy positions radial of the disk and the outer ends thereof tend to travel-'in the are A when free of 'the flue walls. Initial contact between the outer end of each chain and flue wall is in the nature of a hammer blow, subsequent contact between the chain and the flue wall in one traverse thereof being in the nature of a wiping contact. Such initial hammer blow and the subsequent wiping or scraping of the flue wall by the outer end of-the chain cracks the slag accumulation and removes it from the flue in the vicinity of the portion contacted by the chain.

In some instances it is suflicient to pass the cleaning head through the flue in one angular position only relative to the flue since the cracking of the accumulation on one side of the corner of the flue tends to loosen it in other positions, such as on the other wallat the other side of the corner. It is preferred, however, particularly in view of the speed with which the operation is accomplished, where the flue is of such dimension as to receive the cleaning head in two angularly spaced positions, to employ a plurality of such. passes through the flue. In the case of the square flue illustrated in Figure 5, after one pass of the cleaning head in the angular disposition shown the head is withdrawn from the flue and reinserted in a position from that in the first pass so that the ends of the chains then act upon the end walls 52 and 54 in locations slightly inwardly of the corners.

' Use of the preferred embodiment of the flue cleaner shown in Figures 1 and 2 has markedly reduced the amount of labor necessary to clean flues in apparatus such as open hearth checkers and hot blast stoves. When the checkers of the ton capacity furnace previously mentioned are cleaned by such apparatus. it is necessary to expend but seven man hours for the total operation. In addition, the overall furnace laydown time to allow such operation is but 8 hours as compared to the 24 hours previously required when the described hand cleaning methods were employed.

Having thus fully disclosed prefered embodiments of the method and apparatus for cleaning flues in accordance with the teaching of the invention, I desire to claim as new the following:

1. A method of cleaning flues having two opposed longitudinal corners comprising progressively subjecting the flue longitudinally thereof in two opposed locations in the vicinity of and on one side of said corners, to successive impacts followed by wiping contact by at least one flexible member the outer end of which travels in an approximately circular are when free of contact with the flue, said are intersecting the flue surfaces adjacent each of said opposed corners and lying substantially in a plane containing the opposed flue corners, and repeating the process above described with the flexible member contacting the flue surfaces on the other side of each of the opposed corners.

2. A method of cleaning a flue having a passage in the form of a parallelopiped and a rectangular cross section having opposed side and end walls comprising progressively subjecting Meant cent its corners, to successive impacts iollowed two opposed side walls adjacent the other end 10 wall of the flue, the outer end of each flexible member traveling in an approximately circular arc when tree 0! contact with the flue, laid arcs intersecting the opposed flue side walls and 1!- ingsubetantiallyinaplaneparalieltotheflue end walls, and repeating the process above described with the flexible members contacting the opposed end walls of the flue in the vicinity of the corners.

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summons cum The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 1,810,898 Fletcher July 10, 1929 1,796,458 Henchen Mar. 1'1, 1931 1,874,290 Aurand Aug. 30, 1932 1,917,388 McCarthy July 11, 1933 1,951,851 Turner Mar-.720, 1934 2,151,671 v Wright Mar. 21. 1939 A v roman rs'rm'rs Numher Country Date 1 94.566 Great Britain 1909 8,117 Great Britain 1911 595,596. Germany Apr. 16, 1934 647,912 Germany Jul! 14, 193'! 857,991 Germany n-..- Mar. 19, 1939

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